The calculated distance (air line) between Uster / Kirch-Uster and Schaffhausen is approximately 25 miles respectively 40 kilometers.
By car or train, the actual journey to Schaffhausen is certainly longer, as only the direct route (as the crow flies) between Uster / Kirch-Uster and Schaffhausen has been calculated here.
Air line (approximately)
40 kilometers
21 nautical miles